The kinetics and molecular weight averages of the hyperbranched polymers formed by the alternating copolymerization of equimolar allyl methyl maleate (AMM) and N-n-propyl maleimide (PMI) were investigated. The yields, molecular weight averages, and polydispersity indices as well as the branching degrees of the produced copolymers increased with increasing initiator concentrations and prolonged polymerization time. The trends of the experimental molecular weights as determined by size exclusion chromatography were in good agreement with the theoretical predictions. The molecular weight distribution indices fit the curve given by M-w/M-n = 1/(1-x(D)), and the molecular weights fit the curve given by M-w = 4076/(1-x(D))(2), where x(D) was the conversion of vinyl groups. DSC studies demonstrated a nonlinear relation of T-g values to the reciprocal of molecular weight (M), and T-g values decreased with the increase of molecular weight. For the T-g values of highly branched polymers in high molecular weight range, a relation of T-g = T-g infinity(0) + k/M was obtained, where T-g infinity(0) was obtained by extrapolating to infinite molecular weight and k was a constant. T-g infinity(0) was 136 degrees C, and k = 2.9 for this work. (C) 2005 Wiley Periodicals, Inc.